White-nose syndrome (WNS) is a disease that affects hibernating bats and is caused by a fungus, Pseudogymnoascus destructans, or Pd. Pd is psychrophilic – meaning it grows well in cold, damp places – the same areas bats inhabit. While bats are hibernating, Pd grows on their wings and causes behavioral changes that alter their energetics. Though the exact mechanism of what causes infected bats to change their behavior is unknown, we suspect it has to do with water loss and other physiological changes causes by the disease.

For more information about Pd and WNS, including its history, current observance maps, and lists of infected species, go to: whitenosesyndrome.org.